1. Field of the Invention
This invention relates to apparatus for making bags from a two-ply web of thermoplastic material, and more particularly to apparatus for providing transverse welds in the web of thermoplastic material and for severing the web at predetermined positions therealong.
2. Description of the Prior Art
West German Patent Publication No. 20 05 040 discloses apparatus for making bags in which the formation of a transverse weld is effected by a pair of oppositely disposed, movable welding jaws in which both an upper and a lower welding jaw is movable relative to the other and toward and away from the web of thermoplastic material from which bags are severed. The lower welding jaw is adapted to be forced by the upper welding jaw into the web cutting plane against a spring force, so that a bag can be severed from the web by cutting the same at a point adjacent to a weld line that is formed by the upper and lower welding jaws. However, that apparatus requires separate moving and guiding means for guiding each of the upper and lower welding jaws, which thereby imparts undesired complexity to the apparatus.
It is an object of the present invention to provide an improved bag making apparatus in which the structure of the apparatus is simplified by fixedly mounting the lower welding jaw and at the same time preventing contact between the web and a severing knife between successive welding cycles.